# FS_SetDefaultDMA

## C Specification

      #include <nitro/fs.h>

      u32 FS_SetDefaultDMA( u32 dma_no );

## Description

When a valid DMA channel is specified, it cannot be used until the setting is changed with the `FS_SetDefaultDMA` function.

If you specify `FS_DMA_NOT_USE`, instead of DMA, it uses the CPU to transfer.

## Caution

When a valid DMA channel is specified, this DMA channel cannot be used until the setting is changed with the `FS_SetDefaultDMA` function.

The file system uses this DMA channel internally to access the NITRO ROM device. Refer to the description on the `CARD_ReadRom` and `CARD_ReadRomAsync` functions.

## Arguments

`dma_no` | The DMA number that the ROM Archive in the file system uses. If you specify `FS_DMA_NOT_USE`, instead of DMA, it uses the CPU to transfer. When a valid DMA channel is specified, this DMA channel cannot be used until the setting is changed with the `FS_SetDefaultDMA` function.

## Return Values

It returns the DMA channel that was previously set.

## See Also

`FS_DMA_NOT_USE`, `CARD_ReadRom`, `CARD_ReadRomAsync`

## Revision History

07/23/2004 Added caution regarding the ROM archive and DMA channel
05/14/2004 Additional description of `FS_DMA_NOT_USE`
04/08/2004 Initial Version